It is known that the properties of paper are affected by the particular pulp employed and the degree of refining carried out on the pulp. It also is known that certain properties such as tear strength reach maximum values at relatively low refining levels. Such papers tend to have relatively low tensile strengths. By increasing the refining level, the tensile strength can be increased with a concomitant loss of tears strength. Other properties such as opacity, fold resistance, compressibility, and surface properties also are affected by the level of pulp refining. Accordingly, in the manufacture of most paper products, the manufacturer must trade off certain properties to optimize other properties considered more important for certain end use applications. Frequently blends of two or more pulps will be employed to obtain a desired balance of properties.
For the above reasons, the art is constantly seeking methods for obtaining a better balance of overall properties in paper which requires smaller trade offs in desired properties.